secondary carb diaphragm

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beaufort-fj60

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I'm changing out the secondary carb diaphragm. Sor has one for $45, napa $14, and all kinds of prices in-between those. Has anyone replaced the rubber in the old diaphragm? That couldn't be more that five cents worth of rubber.
crisp.webp
crisp3.webp
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rchalmers3 said:
Great photos!

I know there are rebuilders who repair rather than replace the assemblies. But they usually are working on obsolete stuff. $14 from Napa seems like a great value. While it's still available that seems like a fair exchange. To me.

Rick
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$14 is cheap, I'll probably go with the Napa one. Just wondering if any other cheap-skates out there tried to rebuild it. :D
 
$14 is cheap.

Amusing repairs:
Seen some diaphragms that were skinned w/ a layer of RTV snot.
Seen some Holley diaphragms w/ Aisan link brazed on to the chopped holley link.
 
FJ40Jim said:
$14 is cheap.

Amusing repairs:
Seen some diaphragms that were skinned w/ a layer of RTV snot.
Seen some Holley diaphragms w/ Aisan link brazed on to the chopped holley link.
Click to expand...

:whoops:$21.74 for part/tax/shipping.. Only problem with the Napa part is; the guy at the store said no stores have the part and it is ordered from the "factory". That either means I'm not going to get it or it will take awhile. wild guess



are most of the diaphragms you see in rebuilds old, torn, and cracked? The one in the above pics sounds like a piece of paper its so dried out.
 
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Click Here: Carburetors

I replaced my diaphragm with the one that came in this kit. If you haven't done a tune recently, do one, otherwise it'd be good to have some spare tune parts around. Mine arrived in about a week.
 
:whoops:$21.74 for part/tax/shipping.. Only problem with the Napa part is; the guy at the store said no stores have the part and it is ordered from the "factory". That either means I'm not going to get it or it will take awhile.

are most of the diaphragms you see in rebuilds old, torn, and cracked? The one in the above pics sounds like a piece of paper its so dried out.
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Yes, they are usually bad after ~20 years.

I've got the diaphragm in stock for about NAPA price. Email me for info.
 
I have replaced the ribber in the diaphragm on several occasions and have learned the hard way. Make sure not to tighten the screws to tight - this will cause warping and leaking. Also placing the bottom of the diaphragm over the rod and then push the rod up so that the spring is compressed before tightening the screws will prevent the rubber from being stretched or wrinkled causing leaks. I have found that even the tiniest leak will render the diaphragm useless. Frankly, I would gladly pay $15- $20 for a new leak free diaphragm. I did not know they were for sale - Thanks!!

-Gargoyle
 
Marc, the secondary diaphragm has vacuum applied to one side of it by passages in the carb. The vacuum overcomes a closer spring and actually pulls open the second barrel on the carb.

When the rubber is cracked and leaky, vacuum cannot build up behind it, so the secondary never opens.

Sadly, this $14 failure has probably lead to several V8 swaps. (nothing wrong w/ a V8, just an extreme solution for a $14 problem).
 
FJ40Jim said:
Marc, the secondary diaphragm has vacuum applied to one side of it by passages in the carb. The vacuum overcomes a closer spring and actually pulls open the second barrel on the carb.

When the rubber is cracked and leaky, vacuum cannot build up behind it, so the secondary never opens.

Sadly, this $14 failure has probably lead to several V8 swaps. (nothing wrong w/ a V8, just an extreme solution for a $14 problem).
Click to expand...


Can you put in a "weaker" closer spring to tap into the secondary a little earlier?
 
is this the spring inside of the diaphragm? .. never mind... I got it.

Vac pulls, overcomes the spring (compresses it inside the diaphragm), rod connected to diaphragm pulls on the end of the secondary butterfly rod, rod turns, secondary opens.
 
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how hard is it to rebuild a carb - there is a guy wrecking a 60 and i was thinking of buying his old carb and rebuilding it - im no mechanic - but i like playing around with fiddly s*** and thought i could rebuild his and when finished swap it for my old had it carb - and worst comes to worst - if i cant put it back together - just hand it over to competent authority


thoughts?
 
kranky al said:
how hard is it to rebuild a carb - there is a guy wrecking a 60 and i was thinking of buying his old carb and rebuilding it - im no mechanic - but i like playing around with fiddly s*** and thought i could rebuild his and when finished swap it for my old had it carb - and worst comes to worst - if i cant put it back together - just hand it over to competent authority


thoughts?
Click to expand...

its easy I re-built mine in the same day that included taking it off and re-installing it all back on the truck. just a buncha little parts but the re-build kit should come with a picture w/ numbers to show u where everything goes in case you forget.
 
FJ40Jim said:
Marc, the secondary diaphragm has vacuum applied to one side of it by passages in the carb. The vacuum overcomes a closer spring and actually pulls open the second barrel on the carb.

When the rubber is cracked and leaky, vacuum cannot build up behind it, so the secondary never opens.

Sadly, this $14 failure has probably lead to several V8 swaps. (nothing wrong w/ a V8, just an extreme solution for a $14 problem).
Click to expand...

Could/Would this cause rough idle?
 
kranky al said:
how hard is it to rebuild a carb - there is a guy wrecking a 60 and i was thinking of buying his old carb and rebuilding it - im no mechanic - but i like playing around with fiddly s*** and thought i could rebuild his and when finished swap it for my old had it carb - and worst comes to worst - if i cant put it back together - just hand it over to competent authority


thoughts?
Click to expand...


Like cruisinfj60 said, the carb rebuild kit comes with a diagram. The factory service manual has a very nice write up on the whole carb rebuild.
 
JLH911 said:
Could/Would this cause rough idle?
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No, not in the least. The entire sec.diaphragm assembly could be left off the carb and it would start & idle fine.
 
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